Every display device has a characteristic response. Accordingly, the rendering of the images generated from identical video data by projectors made by different manufacturers will not always be the same. Consequently, the rendering of a motion picture on the display may not be the rendering approved by the director.
Moreover, the ambient light conditions in which display takes place are not always ideal and may affect the appearance of the displayed images. In particular, projectors vary in regard to output, and a higher environmental light level may be tolerated with the brightest projectors. It may prove difficult for a person to determine the acceptable degree of ambient lighting that will not compromise image quality to an inordinate extent. There is a need to improve or modify the rendering of projected images, for example to approximate more closely the appearance that has been approved by the director.